Separation analysis methods for a sample, such as liquid chromatography, are generally used for analysis or test in the fields of organic chemistry, biochemistry, medical science, or the like. In those separation analysis methods, there are used various reagents such as an eluent for separating the sample, a washing solution for washing a column or a flow channel for the reagent, a diluent for diluting the sample, and a washing diluent for both washing and diluting. Those reagents are conventionally provided under a state of being filled in a bottle made of glass or a resin. However, when the reagent is filled in the bottle made of glass or a resin, there is a problem in that air space is generated in the bottle along with consumption of the reagent so that the reagent is concentrated due to evaporation or condensation of volatile components. Thus, in Patent Literature 1, there is disclosed a flexible reagent bag obtained by processing a lamination of a resin layer and an aluminum foil layer into a bag-like shape as a container that is capable of reducing its volume along with the reduction in the amount of the reagent and is also excellent in preservability of the reagent.
As described in Non Patent Literature 1, the above-mentioned reagent filled in the container is sucked up through a suction nozzle or the like inserted downward into the container from an opening formed on an upper of the container, and is supplied to the analysis device. However, when the remaining amount of the reagent in the container is smaller, the reagent is hardly sucked through the suction nozzle, or air bubbles may be generated due to air sucked together with the reagent. Thus, the reagent cannot be supplied in an appropriate amount, with the result that accurate analysis cannot be performed. As a method for avoiding the suction of the air during the suction of the reagent, there is known a method as disclosed in Patent Literature 2, which involves managing a usage amount of the reagent, and completing the use of the reagent in the container under a state in which the reagent in an amount sufficient for avoiding the suction of the air is left in the container. However, in this method, the reagent remaining in the container needs to be discarded, which is not economical. Some of the reagents to be used in the separation analysis are expensive, such as a dedicated eluent put on sale with a liquid chromatograph, and hence there is a demand to use up the reagent without discarding the reagent to the extent possible. In Patent Literature 3, there is disclosed a reagent container capable of using up the reagent without sucking the air even when the remaining amount of the reagent is extremely small, in which an inclination or a recess is formed on a bottom, and a distal end of a reagent suction nozzle is arranged on a lowermost portion of the inclination or in the recess. However, the reagent container also has a problem in that the suction nozzle is long so that air bubbles are easily generated due to reduction in pressure in the nozzle during the suction of the reagent.
When the flexible reagent bag, such as a bag made of a resin, is set in the analysis device, the following procedure needs to be taken as a general procedure. A cap is removed from the reagent bag, and the bag is squeezed to push out internal air. After that, the reagent suction nozzle is inserted into the reagent container, and then a cap provided to the reagent suction nozzle is tightened to hermetically seal the bag. However, when the air cannot be pushed out sufficiently from the container in the above-mentioned procedure, the air space is generated in the container, which may cause the above-mentioned problem about the concentration of the reagent. Further, the above-mentioned procedure requires a skill of a user. In addition, when mounting or removing the cap or pushing out the air from the bag, the user may touch the reagent or contamination of the reagent may occur.